In recent years, the LED lamp instead of the traditional incandescent lamp has been widely used as lighting source. With the increasing requirement of LED lighting source and the development of LED technology, the dimming LED lighting source is came into being. However, linear constant current drive silicon controlled dimming circuit of existing LED lighting source can achieve monochrome brightness adjustment only, but cannot adjust color application, namely the LED lamp cannot provide the effect of linear color temperature adjustment. Although some LED lamps can adjust color temperature, the effect of color temperature is achieved by using expensive microcontroller technology.